Leaf spring-mounted shutter device activated by the interruption of electrical power



,c. R. HUDGENS 3,418,475 UTTER DEVICE ACTIVATED BY THE OF ELECTRICAL P Aug. 19, F

OWER

Dec. 24, 1968 LEAF SPRING-MOUNTED SH INTERRUPTION Filed INVENTOR. Claude R. Hua'gens ATTORNEY United States Patent 3,418,475 LEAF SPRING-MOUNTED SHUTTER DEVICE ACTIVATED BY THE INTERRUPTION OF ELECTRICAL POWER Claude R. Hudgens, 610 Skyview Drive,

West Carrollton, Ohio 45449 Filed Aug. 19, 1965, Ser. No. 481,147 1 Claim. (Cl. 250-105) ABSTRACT OF THE DISCLOSURE A safety device for shielding against radiation emitting sources comprising a spring loaded and normally closed shutter, means for opening said shutter, and electrical means for securing said shutter in the open position as long as electrical power is maintained thereto.

This invention relates to safety shutter devices and more particularly to a safety shutter device for X-ray or other radiation emitting machines or devices.

As X-ray or other radiation emitting machines increase in size and output, the danger of exposure to the radiation from the tube or source increases correspondingly. Without a safety shutter effectively blocking the source of the radiation, the technician adjusting the machine, or the sample or specimen being examined, is constantly in danger from exposure to the residual or other radiation emissions which may emanate from the source, even in instances where the power is off. Such radiation on a cumulative or other basis may be extremely dangerous to the technician.

Hence there is a need for a safety device to prevent accidental exposure to radiation from X-ray tubes or other sources. Such a device should preferably require manual retraction from the closed or safety position, but should have an automatic feature which returns it to the closed or safety position.

The present invention satisfies the need for a safety device as discussed above by providing a safety shutter which prevents the passage of radiation from the source through the collimator.

An object of the present invention is to provide a new and improved safety shutter for an X-ray or other radia tion emitting machine.

Another object of the invention is to provide a safety shutter which is characterized by ,few moving parts and is thus highly reliable.

Another object of the invention is to provide a safety shutter which has both manual and automatic operation capabilities or features.

This specification, including the description, drawing, and claim, has been prepared in accordance with the requirements' or provisions of the patent laws and the rules promulgated under the authority thereof.

In the accompanying drawing:

FIG. 1 is an end view of one embodiment of the present invention;

FIG. 2 is an end view showing another embodiment of the present invention with alternative features; and

FIG. 3 is a sectional view showing the relationship of the shutter to the source and the collimator.

The embodiment illustrated in FIG. 1 discloses an X-ray tube or other radiation source 10, which is normally covered by a shutter 11 to prevent the emission of radiation through the collimator 25 (see FIG. 3). The shutter may be of lead or other radiation absorbing material, if alpha, beta, or gamma rays are to be absorbed, or in the case of neutron absorption, a hydrogenous material may be laminated with lead or some other type shielding. The shutter 11 is urged to the covered or closed position as shown "ice in phantom by a leaf spring 17, enlarged for illustrative purposes, secured to the machine as at 18 and may be manually removed from and returned to such position by a handle 12 and is held in the open or uncovered position as illustrated by an electromagnet 13 which abuts a shoe or plate 14 comprised of a magnetic material, such as iron, secured to the spring 17. The electrical circuit to the electromagnet 13 is completed when the shutter 11 has been manually moved to the open position which allows electrical contact 15 secured to the spring 17 to touch contact 16 secured to the electromagnet. Slight variations in wear, axial alignment, etc., between the electrical contacts 15 and 16 and the electromagnet 13 and shoe 14 may be compensated for in many ways, such as, for example, providing a slight spring bias for the contact 15. The electrical circuit may be completed through the electrically isolated and conductive spring 17 or through a separate wire 20, either of which may be connected to manual and automatic timing switches 19. A leaf spring may, for example, be coated with a suitable plastic, or, on the other hand, may comprise a plastic spring having embedded therein a conductor. An indicator light 21 may be placed in thecircuit to show when the shutter is in the open position. An added safety feature may comprise placing the light in series so that a burned out bulb will automatically open the circuit and cause the shutter to close.

While the embodiment of FIG. 1 is preferred due to its few moving parts, and hence freedom from inadvertent jamming during operation, there is shown in FIG. 2 an embodiment wherein the shutter 31, rather than moving arcuately as in FIG. 1, moves in a straight line manner in guide means 35 to cover or uncover the tube or source 10. The shutter 31 is urged to the closed position either by a tension spring 37 secured to a post 38 on the shutter and to the machine as at 39 or by a compression spring 40 secured to the post 38 and to the machine as at 41, or by both springs, if desired. Handle 32 is provided to move the shutter manually, and electromagnetic means 33 are provided to hold the shutter in the open position. Since the shutter is made of lead or some other radiation absorbing material, presumably non-magnetic, a shoe 34 of magnetic material secured to the shutter is provided to abut against the electromagnet 33. An indicator light 21 is placed in series with the electromagnet as in the previous embodiment.

In some cases it may be desirable to provide automatic means for moving the shutter to the open position. For such a purpose a solenoid 36 may be used. The solenoid servesto both move the shutter and to hold it in the open position.

FIG. 3 shows the shutter 31 disposed axially aligned with and intermediate the X-ray tube or source 10 and the collimator 25, in close proximity to the tube. Flanges 42 and 43 of the shutter 31 may overlap the leading (or head) portion of the tube 10.

The size and thickness of the shutter vary, of course, according to the size and output of the radiation source. It has been found, however, that a A; inch thick lead shutter is satisfactory for most applications.

Any suitable mountings, guide and stop means, switches, etc., may be used and therefore have not been shown in detail. Furthermore, the configuration of the shutter, while disclosed as substantially square, may be round, oval, or otherwise.

It will be seen that the described device provides a new and improved shutter combination for preventing emission of radiation from X-ray, cobalt or other emitting machines or devices at other than desired periods. The device is of simple and inexpensive construction, for relatively foolproof operation.

I claim:

1. A safety device for shielding against X-rays after interruption of electrical power in combination with a support, an X-ray source and an apertured collimator comprising a lead shutter normally disposed in a normal first position overlying said source intermediate said source and said collimator and in alignment with said source and the aperture of said collimator, manually operable means for moving said shutter to a second position out of alignment with said source and collimator aperture, an elongated electrically conductive leaf spring member having one end portion fixedly attached to said support at a location spaced from said source and secured adjacent an opposite end portion to said shutter and in unflexed condition normally maintaining said shutter in said first position overlying said source, said member being rotatable about its fixedly attached end portion to a flexed condition with said shutter in said second position out of alignment with the source, electromagnetic holding means adjacent said second position for holding said leaf spring member in flexed condition and shutter in said second position when supplied with electric current, magnetic material means carried by said leaf spring member for magnetically engaging said electromagnetic holding means, an electrical contact carried by said leaf spring member for closing a circuit through said electromagnetic holding means when said shutter is in said second position,

References Cited UNITED STATES PATENTS 3,046,430 7/1962 Green 250106 X 3,069,549 12/1962 Thompson 250105 FOREIGN PATENTS 442,401 3/ 1927 Germany.

OTHER REFERENCES Preliminary Report on a Complete Portable Field X-Ray Unit, report No. 168, by A. W. Carpenter et al., X-ray Department, Army Medical Research Laboratory, Fort Knox, Ky., Nov. 26, 1954, ,pp. 2 to 5 and 9.

WILLIAM F. LINDQUIST, Primary Examiner.

US. Cl. X.R. 250l08 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,418,475 December 24, 1

Claude R. Hudgens It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 5 and 6, "Claude R.

610 Skyview Drive, west Carrollton, Ohio 45449" should read Ohio, assignor to the United States of tomic Energy Commission Hudgens, Claude R. Hudgens, West Carrollton,

America as represented by the United States A Signed and sealed this 10th day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JP

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

